The fertilizer plant that exploded and wiped out much of a small Texas town last week once stored 1,350 times the amount of ammonium nitrate that typically triggers federal safety oversight, officials said.

Yet a person familiar with Department of Homeland Security operations said the company that owns the plant, West Fertilizer, failed to tell the agency about the potentially explosive fertilizer it stored last year, as required.

The fiery explosion Wednesday killed at least 14 people in West, Texas.

Fertilizer plants and depots must report to the DHS when they hold 400 pounds or more of ammonium nitrate.

Filings this year with Texas state officials, who didn’t share the data with the feds, show the plant last year stored 270 tons of the fertilizer ingredient.

A congressman is asking if incomplete disclosure or regulatory gridlock contributed to the disaster.

“It seems this manufacturer was willfully off the grid,” said Rep. Bennie Thompson (D-Miss.), ranking member of the House Committee on Homeland Security. “This facility was known to have chemicals well above the threshold . . . yet we understand that DHS did not even know the plant existed until it blew up.” Company officials did not return calls seeking comment.